1. Field of the Invention
The present invention relates to an automatic tool storing mechanism equipped with a magazine to store a large number of tools and pots.
2. Description of the Related Art
Most machine tools, especially machining centers, are equipped with an automatic tool exchanging mechanism. They recently need a large number of tools. They are provided with many magazines to store the increased tools. Each magazine stores a large number of pots which are connected by chains. Pots are provided with a variety of tools.
A conventional automatic tool exchanging device, as disclosed in Japanese Patent Laid-open Nos. 2003-291046 and 2008-155343, is composed of a magazine holding a large number of tools and pots, means for taking out a tool (held in a particular pot) from the magazine and transporting it to a waiting position, and a tool exchanging arm which exchanges the unused tool (which is waiting at the waiting position) for the used tool (which is attached to the main spindle).
The conventional automatic tool exchanging device is so designed as to take out a selected tool from those which are arranged in the magazines. This action is accomplished by grabbing the tool with claws by its V-shaped flange. The pot from which the tool has been taken out is left in the magazine, and only the tool is transported from the magazine to the waiting position.
According to the conventional method, tool transportation is accomplished by separating a tool from the pot and grabbing it with claws by its V-shaped flange. The disadvantage of this method is that a heavy or long cutting tool is liable to lean during transportation, thereby causing instability in long or fast transportation.
Moreover, the claws need high rigidity to firmly grab the tool by its V-shaped flange.
The present inventors have developed an automatic tool storing mechanism which ensures stable tool transportation without tools leaning even in the case of heavy or long cutting tools, as disclosed in Japanese Patent No. 4972120.
The automatic tool storing mechanism disclosed in Japanese Patent No. 4972120 will be described with reference to FIGS. 1 to 10.
FIG. 1 is a diagram showing how the automatic tool storing mechanism takes out an unused tool and a pot together from one magazine, transfers them to the waiting position, and exchanges the unused tool for the used tool attached to the main spindle.
FIG. 2 is a diagram showing how the automatic tool storing mechanism returns, after exchange, the used tool and the pot together to another magazine.
The pot (also called tool pot) is common to all the tools (also called tool holder).
In FIGS. 1 and 2, the first magazine 10 stores the tools 12 numbered 1 to 50 and the pot 14. (FIGS. 1 and 2 show only one tool out of 50.) The second magazine 16 stores the tools 18 numbered 51 to 100 and the pot 14. FIGS. 1 and 2 show only one tool out of 50. FIGS. 1 and 2 show only the first and second magazines.
FIG. 1(1) shows one example of the initial state. The tool 12 numbered 1, which is stored in the first magazine 10, is called out or selected by the control means (not shown).
In FIG. 1(2), the tool 12 numbered 1 (which has been called out) and the pot 14 for it are taken out together from the first magazine 10. They are transferred rightward in FIG. 1 and positioned under the pot moving arm 22.
In FIG. 1(3), the pot moving arm 22 goes down and grabs the tool 12 numbered 1 (by its V-shaped flange) and the pot 14 with its claws.
In FIG. 1(4), the pot moving arm 22 goes up so that the tool 12 numbered 1 and the pot 14 are moved to the entrance of the guide 26.
In FIG. 1(5), the tool 12 numbered 1 and the pot 14, which are held by the claws, remain at the entrance of the guide 26, and only the pot moving arm 22 goes up so that the initial state is restored.
In FIG. 1(6), the tool 12 numbered 1 and the pot 14 are moved together to the waiting position along the guide 26 while they are being held.
In FIG. 1(7), the tool exchanging arm 28 exchanges the unused tool 12 numbered 1 for the used tool 18 numbered 51, which is attached to the main spindle 30.
FIG. 1(8) shows the state in which the tool exchange has been completed.
In FIG. 2(1), the used tool 18 numbered 51 (which has been exchanged) and the pot 14 for it are moved together leftward to the entrance of the guide 26.
In FIG. 2(2), the used tool 18 numbered 51 and the pot 14 are positioned under the pot moving arm 22.
In FIG. 2(3), the pot moving arm 22 grabs the tool 18 numbered 51 (by its V-shaped flange) and the pot 14 with its claws.
In FIG. 2(4), the pot moving arm 22 goes up to its initial position while it grabs the tool 18 numbered 51 (by its V-shaped flange) and the pot 14 with its claws.
In FIG. 2(5), the pot moving arm 22 moves to the position for the second magazine 16 while it is grabbing the tool 18 and the pot 14.
In FIG. 2(6), the pot moving arm 22 goes down to the returning position for the tool 18 numbered 51 in the second magazine 16 while it is grabbing the tool 18 and the pot 14.
In FIG. 2(7), only the pot moving arm 22 goes up, away from the tool 18 and the pot 14, to the position for the initial state.
In FIG. 2(8), the tool 18 numbered 51 is returned, together with the pot 14, to the second magazine 16. As the result, the entire system restores its initial state.
FIGS. 3 to 8 show one example of the automatic tool storing mechanism which has been illustrated in FIGS. 1 and 2.
It has a plurality of magazines (say, five magazines numbered 10, 16, 40, 46, and 50) of the same structure, which are arranged in a line in the longitudinal direction.
Each magazine (10, 16, 40, 46, or 50) is rotatably arranged so that the pots 14, which are common to them, make a circle endlessly. Each pot 14 is provided with a variety of tools 12 and 18 (only for illustration in FIGS. 1 and 2).
The total number of the pots 14 that can be stored in all the magazines may be several hundreds (say, 300).
The specific pot 14 provided with the tools 12 and 18 is selected (or called out) by the control device (not shown), and then it is transferred from the position 90 close to the magazine (shown in FIG. 4) to the waiting position 100 close to the main spindle by the transporting means (mentioned later).
The guide for pot transportation is comprised of the first guide part 51 and the second guide part 26. The former, which is close to the magazines, is positioned in front of each magazine, and the latter is positioned between the former and the waiting position 100.
The pot moving means has first driving means and second driving means, and the pot moving arm 22. The first driving means 55 (which is preferably a hydraulic cylinder) moves the pot provided with tools horizontally between the first guide part 51 and each magazine. The second driving means 101 (which preferably includes a ball screw and a servo motor) moves the pot provided with tools horizontally along the second guide part 26. The pot moving arm 22 moves the pot with tools vertically between the first guide part 51 and the second guide part 26.
As shown in FIG. 5, the automatic tool storing mechanism has the two rail-like guides 61 for the pot moving arm which run parallel horizontally on both sides thereof. Along the guide 61 are arranged other magazines in a line.
The pot moving arm 22 is moved up and down by the vertical driving part 71.
It is moved horizontally to the position of the selected magazine along the two guides 61 for the pot moving arm by the running driving part 77 (which preferably contains a reducer and a servo motor) through the two belts 73 and 75 extending on both side of the automatic tool storing mechanism.
The first guide part 51 is positioned as desired in the longitudinal and lateral directions by the two guides 61 for the pot moving arm 22.
This is explained with reference to FIG. 6.
Of the many tools stored in the first magazine 10, the tool 12 numbered 1 is selected (called out) by the control device (not shown). The tool 12 numbered 1 and the pot 14 for it are pushed out together from the first magazine 10 by the hydraulic cylinder 55 installed at the pot entrance and exit of the magazine 10. It is transferred rightward (in FIG. 6) along the first guide part 51. At this time, the pot 14 is held by the pot holding part 59 by the action of the pot lock cylinder 57 until the tool 12 numbered 1 and the pot 14 for it reaches the position under the pot moving arm 22.
Then, the pot moving arm 22 is lowered. The V-shaped flange of the tool 12 numbered 1 is grabbed by the claw 22a and two parts of the pot 14 are grabbed by the claws 22b and 22c. 
The symbol 103 denotes the pot lock cylinder to lock and hold the tool and the pot 14 with the claws 22a, 22b, and 22c. 
With the pot lock cylinder 103 activated (in its lock state), the pot moving arm 22 is raised and the tool 12 numbered 1 and the pot 14 are moved together to the entrance of the second guide part 26.
At the entrance of the second guide part 26, the pot holding part 65 holds the pot 14 by the action of the pot lock cylinder 105. With the pot 14 held, the pot 14 and the tool 12 contained therein are transferred to the waiting position 100 by the second driving means 101.
After the unused tool 12 numbered 1 and the pot 14 have reached the waiting position 100, the tool exchanging arm 28 is activated. The paired holding parts 28a and 28b turn to exchange the unused tool 12 numbered 1 for the used tool 18 numbered 51 attached to the main spindle 30. In other words, it detaches the tool 12 numbered 1 from the pot 14 and removes the tool 18 numbered 51 from the main spindle 30 and then it turns them through 180° and attaches the tool 12 numbered 1 to the main spindle 30 and places the tool 18 numbered 51 in the pot 18.
The used tool 18 numbered 51 and the pot 14 are transferred to the prescribed magazine along the guide, as shown in FIG. 2. At this time, the pot lock cylinders 103 and 105, the pot moving arm 22, the holding parts 59 and 65, the hydraulic cylinder 55, and others are activated in the order which is reverse to the order in which the pot 14 is transported to the waiting position 100.